1. Field of the Invention
This invention relates to a method and apparatus for continuously supplying a film strip of a thermoplastic synthetic resin, such as vinyl or polyethylene, as a bag or package material, which is extruded from an extruder head, to a printing machine, bag making machine, packaging machine or like machine.
2. Description of the Prior Art
In general, in conventional methods and machines in the art, such a film strip, which is extruded from the extruder head having a rectilinear orifice or an annular orifice, is first wound around a supply reel or roll, and then the strip is supplied from such a supply roll to a machine such as a bag making machine. With such a way of supply or feed of the material film strip to such machine, it is required to repeat the loading of a new supply roll every 15 - 20 minutes because, in general, a roll of such strip or web is 1000 - 1500 m at most in length. Such frequent loading of the new roll is not only troublesome, but also consumes a considerable time and labor. Further, it is necessary to stop operation of the machine each time when a new supply roll is loaded. Consequently, the working efficiency of the machine is decreased, causing the cost of products to be expensive.
The foregoing inconveniences and disadvantages of such prior art can be overcome by providing a method and apparatus which makes it possible to continuously supply a film strip of a thermoplastic synthetic resin to a machine from an extruder head which continuously extrudes a single film strip or a tube which is subsequently formed into a film strip in the form of a collapsed tube.
At the initial stage of operation of the extruder, however, the film strip extruded from the extruder head does not have a regular thickness and breadth which are predetermined and is not suitable for a bag material or a packaging material to be fed to a bag-making machine or a packaging machine. In other words, the film strip formed at the initial stage of operation of the extruder is so irregular in thickness and breadth that it is unsuitable for use as a material for a bag or package which requires precise dimensions. Thus, there arises a problem of how the defective film strip should be dealt with. If such strip is fed to such machine, products which are difficult to reproduce and which require expense for the disposal thereof are continuously manufactured. To avoid such waste of material, it is necessary not to feed such a defective film strip to such machine until the film strip being extruded from the extruder head is formed to have a predetermined regular or uniform thickness and breadth.